Tool holder and guide for grindstones.



No. 709,l78. Patented Sept. 16, I902.

S. C. SCHOFIELD.

TOOL HOLDER AND GUIDE FOR GRINDSTONES.

lAppliation flied Jan. 30,1902.

(No Model.) 2 Sheets-Sheet l.

7/13/1650 es fiufiipr:

@flwj P Y 244 a 3 ,4 W0 75 Patented Sept. l6, I902.

s. c. S CHOFIELD. TDOL HOLDER AND GUIDE FOR GRI NDSTONES.

(Application filed Jan. 30, 1902.)

2 Sheets-Sheet 2.

(No Model.)

' UNiTED STATE PATENT OFFICE.

sILAsc. SCHOFIELD, or FREEPO'RT,'ILLINOIS.

ro'ol. HOLDER AND GUlDEfOR GRINDSTOINES.

SPEGIHCATIQN formingpart Letters Patent No. 709,178, dated September 16, 1902. Application filed mu so, 1902. Serial No. 91,334. (No model.)

. To all wit-0721, it may concern;

Be it known that -I, Sims .0. SCHOFIELD, a citizen of the United States of America, residing at Freeport,'in the county of Stephenson and State of 'Illinois, have invented certain new and usefulImprovements in Tool Holders and Guides for Grindstones, of which the following is specification.

- Myinvention relatesto certain'new-and usefor grind'stones, the particular object of my invention being to produce a guide and toolholder which will take a cutter of the ordinary three or.four-spiral-bladed lawn-mower and serve as a proper holderand tool-guide for the same while it' is being ground.

To this end my inventionconsists 'in certain novel features of construction, which are fully shown in the drawings, and described in the specification.

In the drawings, Figure-l is a perspective of a grindstone of the ordinary type having my tool guide and holder with a lawn-mower blade in the position for grinding. Fig. 2 is a front elevationof the tool holder and guide with a slight portion of the frame of the machine. Fig. 3 is a section in the line 3 3 of Fig. 2. Fig. 4 is a top view of the grindstone and the guide proper as distinguished from the tool-holder; and Fig. 5 is a detail section in the line 5 5 of Fig. 2, showing the construction of the cutter-centering mechan' ism, the cutter-shaft being shown in elevation in said figure.

, In the drawings, A is a suitably-driven emery-wheel journaled in theextremities of the two arms a, as shown in Fig. 1, and B is the base of the machine immediately below the grindstone, suitably perforated, as shown'in Fig. .4.' Above the base 8 isa plate C, perforated longitudinally of its length by the slot The plate (i is adjustably clamped in place .by means of the bolt 0 and has on its extremity farthest removedfrom the slot 0 the boss 0, provided with a clamping-bolt 0. Within the boss C runs an upright arm (I, vertically adjustable and held in place by the boltc'. This arm is shown as havinga round- 7 ed beveled top, as seen in Figs. 3 and 4, which forms the guide proper against which the bladercsts, as distinguished from the cutterholder. Upon the base B and between it and ful improvements in tool holders and guides the plate horizontallymovable to and from.

the axis of the grindstone. The plate 6 is provided'with an arm E", Fig. 4, containing at its ends two conical depressions. Upon this arm is pivotally swung the cutter-holder by means of pointed-screws e entering the conical depressions of the arm E of the plate E. The cutter-holder consists of a bar F, bolted to the frameworkf, which is swung upon the plate E, as above described. Upon the ends of this bar are two upwardly-projecting arms F, having at their upper extremities the two journal-boxes f, Figs. 1 and ,2. Through each of the journalsf runs a shaft G. and these two shafts are connected by the yoke iii, the three parts together forming the solid piece. The whole is both rotatably and lougitudinally movable with respect to the arms F. The inner ends of the shafts can be longitudinally moved with respect to the yoke and they can be clamped in place by the setscrew h of the yoke, thereby varying the distance between them. The said inner ends have conical projections (see Fig. 5) to fi-t suchcutter-shafts as happen to becentered, and they are also provided with removable caps I, conically apertured and adapted to center cutter-shafts which have not been centered in a lathe. The operation of the device is substantially as follows: The cutter is placed between the inner ends of the shafts and centered either by the conical projection 01' by the removable cap I with respect to the shafts. tightly against it and secured by tightening the screw h. The tool-holder is then swung so as to permit the cutter to take the position shown in Fig. 3, where the blade is in contact with the guide proper. is then revolved in the direction shown by the arrow in Fig. 3, which tends to hold the blade firmly against the guide, and it is moved longitudinally by means of the yoke II, the shafts G sliding in the journals f to permit the movement. It will be seen that this holder furnishes a very convenient and simple device for holding a lawn-mower cutter, and it certainly greatly simplifies the The shafts are then pushed' The grindstone too grinding of the same, to say nothing'of the I fact that it produces a much better job than can be done by hand, as a perfectly even edge is obtained without any special skill on the part of the operator.

I realize that considerable changes can be made in the details of this construction, and I do not intend to limit myself to the specific form herein set forth,

I claim as new and desire to secure by Letters Patentl. The combination with a suitable grindstone and frame, of a frame pi'rotally connested to the supporting-frame of said grindstone, a suitable longitudinally-movable yoked shaft journaied in said frame, suitable means for supporting a lawn-mower eutter within said yoke in line with said shaft,

and a suitable tool-guide adapted to (ix the position of the blades of said cutter with reference to said grindstone; substantially as v described.

for holding an: ordinary fawn-mower cutter in place between the inner ends of said shafts;

substantially as described.

3. In aidevice of the class described, the

combination with two shafts arranged in line Y and having a gap between them, of removable eonieally-socketed caps adapted to fit over the ends of said shafts and center a third shaft; substantially as described.

4. A tool guide and bolder consisting of the plate, E, adapted to be clamped to the supp0rting-base of a grindstone, a tool-guide proper adapted to be adjustably clamped with reference to said g rindstone, a frame pivotally connected to said plate, E, said frame consisting of a bar, F, upright journaled arms, FT, thereon, two shafts, G, supported by said arms and having a gap between their inner ends, and a yoke, H, spanning said gap,

and means for supporting a lawn-mower'cutter between the inner ends of said shafts; substantially as described.

Inwitness whereof I- have hereunto set my hand, at Freeport, in the county of Stephenson and State of Illinois, this 25th day of January, A. D. 1902.

' SILAS C. SOI'IOFIELD.

\Vitnesses:

JAMES II. STEARNS, OSCAR R. ZIPF. 

